Means for preventing the fouling of ships&#39; and like propeller shafts and propellers



Nov; 15, 1927.

F. MEANS FOR PREVENTING PROPELLER A LAKE OULING o 6 2 Sheets-Sheet 1 F FTS AND PRO mil 192 File s w U -m wm ll lb &

1, 9,657 IPSANDVLIKE ERS Nov. 15, 1927.

. F. J. BLA MEANS FOR PREVENTING THE FOUL 0F SH PROPELLER SHAFTS AND PROPELL Filed April 1 1926 2 Sheets-Sheet 2 Patented Nov. 15, 1927.

UNITED STATES FREDERICK JOHN BLAKE, OE WINQH'ESTER, ENGLAND MEANS FOR. PREVENTING THE FOULIN'G OF SHIPS AND LIKE PROPELLEB SHAFTS AND TBOPELLEItE-i.

Application filed; April. 19, 1926, Serial No. 103,040, and in Great Britain April 24, 1925..

This invention relates to new or improved means for preventing the fouling of ships and like propeller shafts and propellers As is well-known, the propellers and propeller shafts of ships. can becometouled very easily by wire and other ropes, and the like, which wind around the propeller shaft and seri ously interfere with the propulsion. Trail;- ingand other ropes in llfill)01lIS,1"lV6lS and like waters are, consequently, a menace to the safety of a ship. The object of this invention is to provide an improved device of the kind adapted for preventing the fouling before mentioned. and also for severing; any rope or flexible or clinging; object or matter that may tend to become wound around the propeller shaft or parts thereon. the propeller blades themselves not being relied upon for any shearing! action in the performance of the said severance. A further object is to avoid the use of right and left handed parts and to provide a device adapted for effecting! the said severance equally well in either direction of revolution.

According to this invention, the guard device comprises serrated cutters adapted for the severance of a rope or the like drawn across or thing: against such cutters in either direction. The cutting edges are suitably inclined or curved so as to be adapted for the most efiicient cutting action in those directions in which the fouling rope or the like is likely to come within. the influence of the propeller. The said serrated cutters are advantageously formed on ribs and these ribs are preferably formed on segments which are bolted on the bearing boss in spacedrelation fora purpose hereinafter described.

In order to enable the. invention to be readily understood reference is made to the accompanying drawings, illustrating: examples of constructions suitable for use on ships in which drawings Figure 1 is a side elevation of a propeller and a portion of the stern bracket, the boss of the latter being fitted with cutter devices in accordance with these improvements Figure 2. is an end elevation of, Figure 1 with the boss of the propeller broken away.

Figure 3 is a perspective view, to a larger scale, of a segment formed with cutter de vices and adapted for being fitted to the shaft boss or bracket as seen in Figure 1.

Figure 4 is a perslpective view looking up at the underside of igure 3.

Figure 5 is a central vertical section of the device seen in Figures 3 and 4;. y y

Referring to Figures 1 and 2, a is a fourbladedscrew propeller the shaft of which runs in the usual hearing or boss 79 of the stern bracket The guard device comprises. a ring); of segments 0 which are shown bolted to the boss Z) but which may be welded there on as by electric or acetylene welding, if desired, or which may be fixed thereon in any other appropriate manner. It is particularly important that, whenever possible, the. guard device shall be permanently fixcd by welding or otherwise to the hulloi the ship and form part thereof and so as not to be liable to be lost at seaowing to vibration caused by the running; of shafts which may transmit large powers at high speed. The ring; of segments. a may extend completely around the shaft and they-may be spaced apart'as shown Or, the segmentsmay extend around only a portion of the circle As seen in Figures 1 and 2', and with greater clearness in Figures?) to 5. each segment is stepped at d and across and beyond the step there extends a rib 6 having its outer edge or surface formed as a serrated cutter Each segment may have a number of such ribs if desired. Looked at from the end, andas seen clearly inFic ure 3 the serated edge may: comprise a central ridge of serrations f flanked. by side ridges/ of serrations f of less height. The serrated surfaces 1'' 7 may incline or curve towards the centre of the shaft Erom the rise of the step (Z to the verge thereof, and from this latter point the rib 0 may be extended as at e and also curve towards the centre of the shaft as shown, Thefree, end of the extension 6' may be formed with a dovetail projection 9 having its top and bottom surfaces hollowed out as at h h to produce cutting edges and extending close to the boss of the propellers as seen in Figure 1. The rib extension 6 may be hollowed out on the underside, as indicated at e in Figures 41 and 5, to form further cutting edges j which may be suitably curved and serrated. On either side of each rib. and at a suitable distance therefrom, fillets k may be provided in the angle of the step d and the outer edges of these fillets 7c are formed with serrations Z. The complete device may be produced in cast steel, and all serrated edges may be hardened and de signed and sharpened so as to retain a good 

